COLL 368 |
| Peter G. Vekilov, Dimiter N. Petsev, Simon Brandon, and Panagyotis Katsonis. Department of Chemical Engineering, University of Houston, Houston, TX 77204-4004 |
| We link the specificity of phase behavior – lack of liquid-liquid separation and temperature-independent solubility – to intermolecular interactions in the solution characterized using light scattering. Results indicate in the presence of Na+ and Cd2+ ions the intermolecular interaction potential has a repulsive part due to Na+ assisted hydration sphere build-up at separations between 0.5 and 3 nm, and a short range (<0.2 - 0.1 nm) attractive part due to Cd2+ mediated bonds. To link the found structured potential to the phase diagram we carried out Monte Carlo simulations, using Gibbs-Duhem and Gibbs Ensemble techniques, with an intermolecular potential having a minimum and a local maximum at separations longer than those of the minimum. Increasing the height of the maximum resulted in steeper liquidus lines, and eventually, in temperature-independent solubility. Another consequence of the increasing maxima was the shift of the liquid-liquid separation line to lower temperatures, not accessible in an experiment. |
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Colloidal and Molecular Electro-Optics
Division of Colloid and Surface Chemistry |